Feed device for feeding of assembly parts

ABSTRACT

The invention describes a feed device that feeds assembly parts such as nuts, bolts, and rivets, from a sorting unit to the feed channel of a processing device for pressing or mounting of assembly parts to sheet metal. The feed device consists of a nozzle with a nozzle channel through it connected on one end to a feed line coming from the sorting unit. A protrusion of the nozzle can deploy into a recess opening of a guide piece of the processing device so that the nozzle channel will open laterally into the feed channel of the device. To connect the nozzle to the guide piece, two levers linked to the nozzle are used; they are pretensioned by springs in a closed position surrounding the guide piece and can be moved manually, possibly with the assistance of a tool, into an open position. In this manner the feed device can be easily connected to the processing device and then detached from it.

BACKGROUND OF THE INVENTION

The invention pertains to a feed device for feeding assembly parts, inparticular nuts or other elements, to a feed channel of a processingdevice.

Processing devices of this type pertain primarily to punching mechanismsused to press nuts or other assembly parts into sheet metal. The feedchannel is usually formed in a guide piece that is flexibly bracedagainst the upper press part so that during a downward movement of theupper press part, a plunger will drive one nut through the feed channel.

The nuts are transported by a sorting unit through a preferably flexiblefeed line (e.g., hose) to the punching mechanism. The transfer of nutsfrom the end of the feed line to the feed channel is performed by thefeed device which must be connected to the guide piece of the punchingmechanism for this purpose. This has been done for example, by screwingthe nozzle of the feed device to the guide piece of the punchingmechanism. Connection and disconnection of the feed device are thereforecumbersome and comparatively time-consuming. In addition, the known feeddevices are frequently of complicated design, expensive to manufactureand break down easily.

BRIEF SUMMARY OF THE INVENTION

The invention provides a feed device that will allow a fast and simpleconnection and disconnection together with a simple design.

The problems encountered in previous systems are solved by the presentinvention. Briefly, the preferred embodiment of the present inventionhas two levers that are linked to opposing sides of a nozzle, The leversare pretensioned by springs to a normally closed position for connectingthe nozzle to a guide piece. The levers can be pivoted manually to anopen position to release the nozzle from the guide piece.

In the feed device designed according to this invention, the two leverscoupled to the nozzle provide the connection with the guide piece.Therefore the connection and disconnection merely require that the twolevers be pivoted between their closed and open positions. This can bedone manually very quickly and easily. Clamping or release of screws orsimilar attachment elements is not necessary. The simple connection anddisconnection are achieved by a comparatively low level of design andmanufacturing effort. At the same time, a precise control of theelements between the feed line and the feed channel is assured.Moreover, the invention is distinguished by operating reliability andhaving a long service life.

The feed line can be designed as a hose leading to a sorting unit or toanother source. Another possibility is to design the feed line as amagazine channel of a magazine attached to the nozzle, where themagazine holds a specific number of assembly parts. In this case afilling device can be provided that is connected to the nozzle of thefeed device for filling the magazine.

According to another refinement of the invention, a locking mechanism isprovided at the nozzle which locks the levers in their closed positionwhen in the connected state. This provides additional security againstaccidental opening of the levers.

Other favorable embodiments of the invention are described in theDetailed Description of the Invention and the claims and are shown inthe drawings, a brief description of which follows,

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 A longitudinal cross section through a feed device connected to aguide piece of a punching mechanism;

FIG. 2 A cross section viewed in the direction of arrow II in FIG. 1;

FIG. 3 An end view of the feed device of FIGS. 1 and 2, viewed from theright side in FIGS. 1,2;

FIG. 4 A longitudinal cross section through another application exampleof a feed device which is equipped with a magazine for nuts;

FIG. 5 A plan view of the feed device of FIG. 4;

FIG. 6 A longitudinal cross section through the feed device of FIGS. 4and 5 and a punching mechanism with connected feed device;

FIG. 7 A longitudinal cross section corresponding to FIG. 4 through amodified design of the feed device according to FIGS. 4,5;

FIG. 8 A partially cutaway side view of a filling device for filling themagazine of the feed device according to FIGS. 4,5;

FIG. 9 A partially cutaway plan view of the filling device according toFIG. 8.

DETAILED DESCRIPTION OF THE INVENTION

The left portion of FIGS. 1 and 2 shows part of a processing device inthe form of a punching mechanism or installation head 2 that is used forpressing nuts M into a piece of sheet metal (not shown). The nuts M arefed by a sorting unit (not shown) through the feed device 4 by means ofa flexible or solid feed line 26 designed, for example, as a hose.

The punching mechanism 2 features a two-part 6a,b guide piece 6 that isflexibly braced against an upper press part (not shown) that moves upand down; this press is also provided with a feed channel 8. A slidingplunger 10 in the feed channel 8 is used to drive a nut M through thefeed channel 8 during a downward movement of the upper press part and topress it into the sheet metal (not shown). During the downward movementof the plunger 10, the nut M is held in position by two retainingcatches 12 indicated in FIG. 2. Furthermore, FIG. 1 shows a sensordevice 14 which determines the presence of a nut M. The remaining designof the punching device 2 is irrelevant for understanding the presentapplication and will not be described further.

The feed device 4 consists of a nozzle 20 in the form of a plate-likecomponent which is equipped with a nozzle channel 22 going through itfor the nuts M. The nozzle channel 22 features a region 24 of expandedcross section which holds one end section of the feed line 26 comingfrom the sorting unit.

In the portion of the nozzle 20 including region 24 with the expandedcross section, there is an open upper side that is sealed off by a clampplate 28. The clamp plate 28 is attached to the nozzle 20 by two screws30 and is used to hold the feed line 26 securely in the nozzle 20 in avertical direction. The feed line 26 is held in the horizontal directionby two cylindrical pins 32.

The nozzle 20 is provided with a protrusion 34 on its end turned awayfrom the feed line 26; this protrusion can be inserted into anappropriately shaped recess opening 36 of the guide piece 6 to make theconnection. The exact positioning of the nozzle 20 relative to the guidepiece 6 is achieved by contact of the protrusion 34 with the wallsurfaces of the recess opening 36 and by contact of the front surface 38of the nozzle 20 adjoining the protrusion 34 with the guide piece 6. Inthis case the protrusion 34 extends up to the corresponding side surfaceof the feed channel 8, so that the nozzle-channel 22 opens directly intothe feed channel 8. In this manner, a reliable transport of nuts M fromthe feed line 26 to the feed channel is assured.

To connect the nozzle 20 to the guide piece 6, two levers 40 are used;they are pivotably mounted by bolts 42 in lateral recesses 44 of thenozzle 20. Each lever 40 consists of one retaining arm 40a and oneactuator arm 40b. The levers 40 are tensioned in the direction of aclosed position by a spring 46 that acts between the actuator arm 40band the nozzle 20.

Protrusions 48 are formed on the retaining arms 40a that are pressedagainst the contact surfaces into the recesses 44 by the pretension ofthe springs 46 when in the disconnected state holding the levers 40 in aspread position. In the connected state (FIG. 2), the retaining arms 40aare pressed by the force of the springs 46 into lateral grooves 54 ofthe guide piece 6. In this case the retaining arms 40a have hook-likeends 50 that surround the guide piece 6 so that the levers 40 hold thenozzle 20 against the guide piece 6 with an interlocking connection. Thehook-like ends 50 are provided with slants 52 on their mutually facingsides; these slants make it easy to push the retaining arms 40a into thegrooves 54 of the guide piece 6.

A catch 56 is pivotably mounted in the protrusion 34 of the nozzle 20.The catch 56 is under the effect of a spring 58. If the nozzle 20 isdisconnected, then the spring 58 presses the catch 56 into a blockedposition in which the catch peak 59 blocks the nozzle channel 22 so thatthe nuts M located in the nozzle channel 22 cannot slip out. If theprotrusion 34 of the nozzle 20 is pushed into the receiving opening 36,then due to contact with one wall of the receiving opening 36, the catch56 will pivot back independently into a position in which it releasesthe nozzle channel 22 (FIG. 2). In the region of the catch peak 59 thenozzle channel 22 is provided with recesses 57 adapted to thecross-sectional shape of the nut M (FIG. 3), these recesses ensuring aprecise control of the nut M in this area.

The nozzle 20 can be optionally equipped with a locking mechanism 60 forthe two levers 40. The locking mechanism 60 features a support 62 thatis attached to the nozzle 20 by the recessed screws 30 in the support62.

A locking element 64 can slide vertically along one contact surface ofthe support 62. The locking element 64 is tensioned downward in a lockedposition by a spring 68 braced against a lateral flange of the support62. It is held in this position by a screw 66 screwed into the lockingelement 64 and extending through a hole drilled in the lateral flange ofthe support 62, whose head is braced against the upper side of thesupport 62.

The locking element 64 is provided with two lateral locking protrusions70 (see esp. FIG. 3) that extend between the two actuator arms 40b ofthe levers 40 in the locked position and thus prevent the actuator arms40b from pivoting inward. The levers 40 are thus locked in their closedposition and can only be opened after an upward movement of the lockingelement 64 into an unlocked position.

The operation of the feed device 4 is probably already mostly evidentfrom the above description. To make the connection, the nozzle 20 withattached feed line 26 is moved up to the guide piece 6 of the punchingmechanism so that the retaining arms 40a with their hook-like ends 50engage in the grooves 54, and the protrusion 34 engages in the recessopening 36. If the feed device 4 is equipped with a locking mechanism60, as shown, then first the locking mechanism 60 must be unlocked bypushing up the locking element 64 so that the actuator arms 40b canpivot inward. When pushing the protrusion 34 into the recess opening 36,the catch 56 will pivot into the release position due to contact withthe side wall of the recessed opening 36 so that the nozzle channel 22will be released.

As soon as front face 38 of the nozzle 20 touches the guide piece 6, thesprings 46 will pivot the retaining arms 40a inward into the closedposition where they will engage in the grooves 54 of the guide piece 6and the hook-like ends 50 will surround the guide piece 6. The lockingelement 64 will be pressed by the springs 68 downward into its lockedposition where the locking protrusions 70 move between the actuator arms40b so that the levers 40 are locked in their closed position.

Now the nozzle 20 is securely attached to the guide piece 6 so that thenuts M can move through the nozzle channel 22 to the feed channel 8.

To detach the nozzle 20 from the guide piece 6, first the lockingelement 64 is pushed upward into its unlocked position against the forceof the springs 68. Next, the levers 40 are pivoted into their openposition by inward pivoting of the actuator arms 40b so that now thenozzle 20 can be withdrawn from the guide piece 6. When the nozzle 20 iswithdrawn from the guide piece 6, the catch 56 will be pressed by thespring 58 back into its locked position to prevent the nuts fromslipping out of the nozzle channel 22. The protrusions 48 on theretaining arms 40a of the levers 40 are pressed by the springs 46 intocontact with the contact surfaces in the recesses 44 of the nozzle 20.The feed device is then ready for a new connection process.

To connect and disconnect the nozzle 20, an auxiliary tool 74 can beused that is shown by dashed lines in FIGS. 1 and 2. The auxiliary tool74 is designed as a block device that is provided on its underside witha recess 76 corresponding to the feed line 26, so that the auxiliarytool 74 can be pushed onto the feed line 26 in a longitudinal direction.

On its front side the auxiliary tool 74 has a ramp surface 78 thatcooperates with a corresponding ramp surface 72 of the locking element64. Furthermore, there are two additional ramp surfaces 80 on twolateral arms of the auxiliary tool 74 that cooperate with the two levers40.

The auxiliary tool 74 can be equipped with a relatively long handle (notillustrated) so that connection and disconnection of the feed device canbe carried out from a relatively large distance, which is importantespecially with respect to safety considerations.

As is readily evident, the ramp surfaces 78 and 80 provide the combinedactuator movement necessary for sliding the locking element 64 and forpivoting the levers 40, both during connection and also duringdisconnection. It is necessary merely to slide the auxiliary tool 74along the feed line 26 in the direction of the nozzle 20.

Obviously also the feed device 4 can be used not only for feeding ofpolygonal nuts, but also for round nuts or even other elements, such asbolts, rivets, etc.

FIGS. 4 and 5 show a modified application example of a feed device. Thesame reference numbers are used where the application example of FIGS. 4and 5 correspond to the previous figures.

The feed device of FIGS. 4 and 5 differs from the feed device of FIGS.1-3 in that the feed line for feeding the nuts or other assembly partsis not designed as a feed hose leading to a sorting unit, but rather itis designed as a magazine 81 that holds a specified number of nuts (orother assembly parts).

The magazine 81 features a magazine channel 82 that is formed by a lowermagazine part 82a and an upper magazine part 82b. The two parts of themagazine 81 extend into the region 24 of the nozzle 20 having anexpanded cross section, and they are held in place there by the clampplate 28 and the pin 32. A slide 84 can move longitudinally within themagazine channel 82.

In the application example of FIGS. 4 and 5, the slide 84 is held undertension by a tension spring 100 in a direction such that it will drivethe nuts stored in the magazine channel 82 in the direction of theoutlet end of the protrusion 34 of the nozzle 20. One side of thetension spring 100 is mounted to a pin 89 attached to the nozzle, andthe other side to a pin 88 attached to the slide 84; the latter pinextends through a longitudinally running lead 86 in the upper part 82 ofthe magazine.

To prevent the nuts from falling out of the nozzle channel 22 and thusout of the magazine 81 when the feed device 4 is in the disconnectedstate, a lock is provided in the form of a bolt 104 that is pretensionedin a position blocking the nozzle channel 22 by means of a leaf spring101 attached to the feed device, and during connection, it isautomatically pressed into a release position.

The feed device shown in FIGS. 4 and 5 is not dependent on a feed hosefor the feeding of nuts, and therefore it can be connected to a "mobile"processing device, which in turn can be used with a moving machine part.FIG. 6 shows this type of application, where the feed device 4 of FIGS.4 and 5 is connected to a punching mechanism 2 designed as a mobileunit.

The punching mechanism 2 features a guide piece 6 in the form of a lowerhousing part that is braced elastically by springs 9 against an upperhousing part 7. The plunger 10 used for punching the nuts is held inplace by a screw 11 in the upper housing part 2 and extends into thefeed channel 8 of the guide piece 6.

As is evident in FIG. 6, the feed device 4 is connected to the punchingmechanism 2 in principle in the same way as the feed device of FIGS. 1to 3. The magazine 81 in the disconnected state is filled with aspecified number of nuts (or example, ten nuts), so that the slide 84moves from the far left position shown in FIG. 6, to far right position,where the nuts are prevented from falling out by the bolt 89. Whenconnecting the feed device 4 to the punching mechanism 2, the bolt 89will move into its release position due to the slanted surface 91. Theslide 84 pretensioned by the spring 100 can then feed the nuts one afterthe other to the feed channel 8, where the nuts are driven out downwardby the plunger 10 due to the relative movement between the upper andlower housing parts 7,6.

Whereas the slide 84 is driven by spring force in the applicationexample of FIGS. 4 to 6, in the application example of FIG. 7 thepretensioning force on the slide 84 is produced by compressed air. Inthis case, a compressed air fitting 105 is provided at the rear end ofthe fluid-tight magazine channel 82; this fitting leads to a hose andthen to a compressed air source. The hose connection can be run to acompressed air coupling (not shown) provided on the nozzle 20 that willautomatically establish a connection to the compressed air source whenconnecting the feed device to the punching mechanism 2.

When filling the magazine 81, a filling device 102 can be used, as isillustrated in FIGS. 8 and 9. The filling device 102 has a similardesign to the punching mechanism 2 in FIG. 6. It features a lowerhousing part 106 and an upper housing part 107, which are elasticallybraced against each other by springs 109 and have a lift limiter in theform of screws 113. A plunger 110 attached to the upper housing part 107extends into a guide channel 108 in the lower housing part 106.

In addition, a transverse passageway channel 115 is provided in thelower housing part 106. On its left end (in FIGS. 8 and 9) a feed hose117 is attached that leads for instance, to a sorting unit or to anotherdevice for output of nuts. Similar to the punching mechanism 2 in FIG.6, the feed device 4 can be connected to the magazine 81 at the filldevice 102, so that the right end of the passageway channel 115 isconnected to the nozzle channel 22 at the protrusion 34 of the nozzle20.

As shown in FIG. 8, the plunger 110 normally assumes a position in whichit blocks the passageway channel 115, so that the nuts cannot slip outof the feed hose 117. Due to a relative movement between the lower andupper housing parts 106,107, the plunger 110 is driven into a positionwhere a lead 119 of the plunger 110 aligns with the passageway channel115. The width of the lead 119 corresponds to that of the nuts. The nutscan then be moved from the feed hose 117 through the nozzle channel 22into the magazine 81.

If the magazine 81 is operated by spring force as in FIGS. 4-6 and 8-9,then the feed force (e.g., gravity) moving the nuts through the feedhose 117 must be great enough to overcome the spring force of themagazine 81. In the application example of FIG. 7 where the magazine 81is operated pneumatically, the configuration is set up so that the slide84 is not affected by compressed air when filling, so that only acorrespondingly small feed force is needed to feed in the nuts.

As shown in FIG. 8, the fill device 102 is provided with a sensor unit120 that monitors the feeding of nuts through the feed hose 117 (e.g.,it counts the number of fed nuts) and once the magazine 81 is filled, itoutputs a signal that moves the plunger 110 (by an unillustrated controlunit) into its position blocking the passageway channel 115.

It is claimed:
 1. A feeding device for feeding fasteners from a supplyof fasteners to an installation head, said feeding device comprising:anozzle connected to said supply of fasteners, said nozzle having a freeend which is adapted to be connected to said installation head, and acontinuous channel for the movement of said fasteners from said supplyof fasteners to said installation head; a coupling device for positivelycoupling said nozzle to said installation head; said coupling deviceincludes at least one lever mounted on opposed sides of said nozzle witheach of said at least one lever being mounted to pivot between aconnection position and a released position; and a movable catchmechanism having a first position wherein said catch intersects saidchannel to block said fasteners from moving through said nozzle, and asecond position wherein said catch es removed from said channelpermitting passage of said fasteners through said channel; biasing meansfor biasing said movable catch to said first position to normally blocksaid fasteners from moving through said mouthpiece, said catch beingurged to said second position against said biasing means as said nozzleis connected to said installation head to permit passage of saidfasteners through said channel into said installation head; whereby saidsupply of fasteners can be interconnected to said installation head bycoupling said nozzle to said installation head such that said supply offasteners is automatically stopped when said nozzle is decoupled fromsaid installation head and is automatically opened when said nozzle iscoupled to said installation head.
 2. The feeding device of claim 1,wherein said free end of said nozzle includes a projection adapted to beinserted into a mating receptacle opening of the installation head tofacilitate the coupling of the feeding device to the installation head.3. The feeding device of claim 2, wherein said channel extends throughthe projection and laterally intersects a feed path extending withinsaid installation head.
 4. The feeding device of claim 1, furtherincluding a guide element mounted to said installation head, said guideelement defining an opening for receipt of the free end of said nozzle,said free end including a projection adapted to be inserted into saidopening to facilitate the coupling of the feeding device to theinstallation head.
 5. The feeding device of claim 4, further including alocking mechanism for locking said nozzle into said installation head bylocking said at least one lever into said connection position; wherebysaid lock locks the lever in a coupled condition.
 6. The feeding deviceof claim 5, wherein said locking mechanism includes a receptacle blockattached to the nozzle and a stop element attached in a movable manneron the receptacle block, said stop element is biased into a lockingposition in which it prevents actuation of said lever by blockingmovement of said lever, said stop element being manually movable to arelease position.
 7. The feeding device of claim 6, further including anauxiliary tool having a slanted surface for disengaging said lock, saidslanted surface being adapted to interact with a corresponding angledsurface located on said stop element to displace the stop element. 8.The feeding device according to claim 7, wherein the auxiliary tool hasadditional slanted surfaces which actuate the coupling device into therelease position during a displacement of the auxiliary tool todisengage the nozzle from the installation head.
 9. The feeding deviceof claim 1, wherein said at least one lever has opposed ends and ismounted for pivotal movement about an axis positioned between theopposed ends of each of said levers, said axis defining two sections ofsaid lever, one of which serves as a holding section and the other oneof which serves as an actuation section.
 10. The feeding device of claim9, further including a spring mounted between the actuation section andthe nozzle.
 11. The feeding device of claim 1, further including a feedline extending from said supply of fasteners and connected to saidnozzle.
 12. The feeding device of claim 1, wherein said catch mechanismis pivotally mounted to a projection and is adapted to pivot from saidfirst position to said second position as a projection is inserted intosaid opening thereby opening said channel for the movement of fastenersinto said installation head, said catch pivoting into said channel uponremoval of said projection from said opening to prevent said fastenersfrom exiting said nozzle.
 13. The feeding device of claim 12, whereinsaid catch mechanism includes at least one arm pivotally mounted to saidprojection, said opening being defined by a wall surface, said armengaging said wall surface to pivot to said second position.
 14. Thefeeding device of claim 1, wherein said catch is automatically biasedinto said channel in the first position to block the fasteners fromexiting said nozzle when said nozzle in a decoupled condition, and saidcatch is pressed into said second position in a coupledcondition;whereby the flow of said fasteners from said supply offasteners is automatically stopped when said nozzle is decoupled fromsaid installation head and is automatically opened when said nozzle iscoupled to said installation head.
 15. The feeding device of claim 1,further including a fastener drive mechanism operatively associated withsaid feeding device.
 16. The feeding device of claim 1, furtherincluding a fastener magazine interconnected to said feeding device. 17.A feeding device for feeding fasteners from a supply of fasteners to aninstallation head, said feeding device comprising:a nozzle connected tosaid supply of fasteners, said nozzle having a free end which is adaptedto be connected to said installation head, and a continuous channel forthe movement of said fasteners from said supply of fasteners to saidinstallation head; a coupling device for positively coupling said nozzleto said installation head; a movable catch mechanism having a firstposition wherein said catch intersects said channel to block saidfasteners from moving through said nozzle, and a second position whereinsaid catch is removed from said channel permitting passage of saidfasteners through said channel, said catch is pivotably mounted to saidnozzle and is adapted to pivot from said first position to said secondposition as said nozzle is inserted into an opening of said couplingdevice thereby opening said channel for the movement of fasteners intosaid installation head, said catch pivoting into said channel uponremoval of said nozzle from said opening to prevent said fasteners fromexiting said nozzle;biasing means for biasing said catch to said firstposition to normally block said fasteners from moving through saidmouthpiece, said catch being urged to said second position against saidbiasing means as said nozzle is connected to said installation head topermit passage of said fasteners through said channel into saidinstallation head; whereby said supply of fasteners can beinterconnected to said installation head by coupling said nozzle to saidinstallation head such that said supply of fasteners is automaticallystopped when said nozzle is decoupled from said installation head and isautomatically opened when said nozzle is coupled to said installationhead.
 18. The feeding device of claim 17, wherein said catch mechanismincludes at least one arm biased to said first position; said leverengaging said installation head as said is nozzle coupled to saidinstallation head and moving to said second position.
 19. A feedingdevice for feeding fasteners from a supply of fasteners to aninstallation head, said feeding device comprising:a nozzle connected tosaid supply of fasteners, said nozzle having a free end which is adaptedto be connected to said installation head, and a continuous channel forthe movement of said fasteners from said supply of fasteners to saidinstallation head; a coupling device for positively coupling said nozzleto said installation head, said coupling device includes at least onelever mounted longitudinally along the side of said nozzle and adaptedto fit within a mating groove formed in a guide element mounted to saidinstallation head, said guide element defining an opening for receipt ofthe free end of said nozzle, said free end including a projectionadapted to be inserted into said opening to facilitate the coupling ofthe feeding device into the installation head, said at least one leverhaving a closed position wherein said lever is adapted to positivelycontact said nozzle to said installation head and a release positionwhere in said lever is adapted to release said nozzle from saidinstallation head; a movable catch mechanism having a first positionwherein said catch intersects said channel to block said fasteners frommoving through said nozzle, and a second position wherein said catch isremoved from said channel permitting passage of said fasteners throughsaid channel; biasing means for biasing said catch to said firstposition to normally block said fasteners from moving through saidnozzle, said catch being urged to said second position against saidbiasing means as said nozzle is connected to said installation head topermit passage of said fasteners through said channel into saidinstallation head; a locking mechanism for locking said nozzle into saidinstallation head by locking said at least one lever into said closedposition to lock the lever in a coupled condition; whereby said supplyof fasteners can be interconnected to said installation head by couplingsaid nozzle to said installation head such that said supply of fastenersis automatically stopped when said nozzle is decoupled frown saidinstallation head and is automatically opened when said nozzle iscoupled to said installation head.
 20. The feeding device of claim 19,wherein said locking mechanism includes a receptacle block attached tothe nozzle and a stop element attached in a movable manner on thereceptacle block, said stop element is biased into a locking position inwhich it prevents actuation of said lever by blocking movement of saidlever, said stop element being manually movable to said releaseposition.
 21. The feeding device of claim 20, further including anaxillary tool having a slanted surface for disengaging said lock, saidslanted surface being adapted to interact with a corresponding angledsurface located on said stop element to displace the stop element. 22.The feeding device of claim 21, wherein the auxiliary tool hasadditional slanted surfaces which actuate the coupling device into therelease position during a displacement of the auxiliary tool todisengage the nozzle from the installation head.